HR: 1330h
AN: A52A-0776    [PDF]
TI: Carbon Kinetic Isotope Effects in the Reactions of Atmospheric NMHC with OH, Cl and O$_{3}$
AU: * Anderson, R S
EM: rebeccah@yorku.ca
AF: Centre for Atmospheric Chemistry, York University, 006 Steacie Science Library, 4700 Keele Street, Toronto, ON M3J 1P3 Canada
AU: Iannone, R
EM: riannone@yorku.ca
AF: Centre for Atmospheric Chemistry, York University, 006 Steacie Science Library, 4700 Keele Street, Toronto, ON M3J 1P3 Canada
AU: Thompson, A E
EM: alex@nature.berkeley.edu
AF: University of California, Berkeley, Ecosystem Science, 151 Hilgard Hall, Berkeley, CA 94720-3110 United States
AU: Huang, L
EM: lin.huang@ec.gc.ca
AF: Meteorological Service of Canada, 4905 Dufferin Street, Toronto, ON M3H 5T4 Canada
AU: Ernst, D
EM: darrell.ernst@ec.gc.ca
AF: Meteorological Service of Canada, 4905 Dufferin Street, Toronto, ON M3H 5T4 Canada
AU: Rudolph, J
EM: rudolphj@yorku.ca
AF: Centre for Atmospheric Chemistry, York University, 006 Steacie Science Library, 4700 Keele Street, Toronto, ON M3J 1P3 Canada
AB: It has recently been shown that stable carbon isotope measurements are extremely useful for better understanding of processes involving NMHC in the atmosphere. Knowledge of the isotopic fractionation associated with the chemical removal of NMHC is vital for the interpretation of these measurements. Oxidation by OH-radicals is by far the most important atmospheric removal process of NMHC. Contributions to isotopic fractionation due to removal by reactions with Cl and O$_{3}$ should also be understood to better interpret stable carbon isotope measurements. From our measurements, in normal urban and background air, reactions with O$_{3}$ account for 15-25% of the isotopic fractionation in light C2-C4 alkenes. In polar sunrise conditions, reactions with Cl atoms may have a significant impact on the isotopic fractionation in light alkanes. An overview of the measured KIEs for the reactions of C2-C9 NMHC with atmospheric oxidants OH, Cl and O$_{3}$ will be presented. Possibilities for using specific structural and thermal dependencies of measured KIEs for estimations of unmeasured KIEs of atmospheric interest will be discussed.
DE: 0317 Chemical kinetic and photochemical properties
DE: 0365 Troposphere--composition and chemistry
DE: 0368 Troposphere--constituent transport and chemistry
SC: Atmospheric Sciences [A]
MN: 2003 Fall Meeting